Socioeconomic-related inequities in child immunization: horizontal and vertical dimensions for policy insights.

Background: The incomplete immunization has potentially exposed vulnerable children, especially from the socioeconomically disadvantage group, to vaccine preventable diseases. The schemes would maximize social benefit only when the immunization is effectively distributed on an equitable principle.

Method: The empirical study is based on unit level data from India's National Sample Survey: "Social Consumption: Health Survey- NSS 75th Round (2017-18) database. The nationwide survey is designed on the stratified multi-stage sampling method with an objective to make the sample representative. The egalitarian equity principle requires that distribution of vaccine should be based on health needs of children, irrespective of their socioeconomic and regional factors and the principle is broadly based on two aspects - horizontal and vertical equity. The horizontal inequity (HI) is a direct form of injustice, when children with equal needs of routine immunisation are treated differentially due to their socioeconomic status, while vertical inequity (VI) is indirect form of injustice when children with differential health needs and risks exposure do not receive appropriately unequal but equitable immunisation. Using Indirect Standardisation Method and Erreygers' Corrected Concentration Index, we measure the degree of horizontal and vertical inequities, and then linearly decompose them to identify the major factors contributing towards the respective indices.

Conclusion: Our findings show that incomplete immunization is significantly concentrated among children belonging to poorer households. After controlling for the confounding effects of need factors, the inequity is still significantly pro-poor (i.e., horizontal inequity). The decomposition reveals that lower education, lower consumption and rural habitation are the major factors driving the corresponding inequity. Further, the differential effect of the needs between all and the target groups (at least based on education), is observed, however, is not statistically significant enough to realize inequity (i.e., no vertical inequity). Overall, the inequity is being induced via non-need factors. We further find that community health services (like anganwadi) have contributed towards reducing the inequity in child immunization significantly. The paper highlights the policy recommendation that the child immunisation program should target factors driving HI and need to align their distribution in terms of risks exposures.